According to the work of Zambryski and Crawford in intercellular shortroot movement in 2000, they found that the shortroot protein (which is a transcription factor) intercellular transport occurs through specific "pores" connecting adjacent cells called plasmodesmata, They could have different states: open or close.
Shortroot and scarecrow proteins are two transcription factors that work together. the evidence that shortroot induces the expression of the scarecrow gene, is that scarecrow mRNA levels are reduced in shortroot mutants. it proves that there's a link between the shortroot protein and scarecrow synthesis.
